Classes and Archetypes: A character can have any number of classes, but may only have one archetype. A class grants basic class features and several choices of talents keyed to one of the six ability scores, while an archetype grants class features and talent choices keyed to a theme or set of skills, such as medicine, crafting, or espionage.

Any character can choose any archetype as long as they can meet the requirements. Every class and archetype has a separate age category, a character must fit within the highest of the two age categories of his starting class and his archetype.

Ability Score Maxima: The base value of an ability score (before temporary bonuses such as Enchantment or Alchemical bonuses are applied) can never exceed 20 + your racial modifier in that ability score (or minus, if it’s a penalty).

Equipment Quality: Unless masterwork in nature, all equipment has the Fragile quality due to wear and tear following the fall of man.

A Fragile weapon that rolls a natural 1 on attack becomes broken. Attacks made with a broken weapon suffer a –2 penalty on attack and damage rolls. Such weapons only score a critical hit on a natural 20 and only deal ×2 damage on a confirmed critical hit.

Fragile armor or shields worm when receiving a critical hit on a natural 20 (but not lower) become broken. The bonus a broken piece of armor or shield grants to AC is halved, rounding down and broken armor doubles its armor check penalty on skills.

Multi-type attacks: Attacks which deal both physical and energy damage only have to deal with the highest of either Damage Reduction of Energy Resistance, not both.

Massive Damage Threshold: Whenever a character takes damage from a single hit that equals or exceeds his current Constitution score, he must succeed on a DC 15 Fortitude save or instantly be reduced to -1 Hit Points.